There is a fundamental difference between an army operating on foreign soil, versus an army operating against its own people. In the former case, the civil service workers who send out the paychecks and purchase orders that keep things running are safely elsewhere, out of reach.
Notice how long it took to nail the "Beltway Snipers". Now visualize a thousand small teams engaged as serial killers of govt employees. How long before people stop coming to work? A govt without clerical workers, is a govt without supplies.
An army without ammo, fuel, food, and clothing is just a ragged mob